This invention relates to a process for the production of higher boiling hydrocarbons from lower boiling hydrocarbons. In another aspect, this invention is particularly concerned with an improved process for the production of higher molecular weight isoparaffins by the alkylation of lower boiling isoparaffins with olefins in the presence of an acidic alkylation catalyst, such as hydrogen fluoride, in which process maximum utilization is made of available low boiling isoparaffin and with the yielding of high purity normal paraffin. In another aspect, this invention relates to an alkylation process having an isoparaffin containing feed fractionation zone, also known as a butane splitter, an alkylation zone, and an alkylation product fractionation zone, also known as a main fractionation zone or iso-stripper zone.
As is well known, hydrocarbon products can be produced by alkylation reactions involving the combination or condensation of two dissimilar hydrocarbon reactants in the presence of suitable catalytic agents. The alkylation of isoparaffins, such as isobutane, with olefins, such as propylene and/or butylenes, is representative of this type of reaction and has been commonly carried out by feeding isobutane and olefin feedstock in the liquid state, along with the hydrofluoric acid to an alkylation reactor. The reaction product stream can be separated into an acid liquid phase and a hydrocarbon liquid phase, which hydrocarbon phase is then passed to various separation zones in order to recover the various components of the hydrocarbon stream. In some alkylation operations, a feed fractionation zone, called a butane splitter, is installed to upgrade low purity isobutane feed to a higher purity isobutane for use in the alkylation reaction. Also, in the alkylation reaction, a recycle isobutane stream is produced as a vapor side draw from the main fractionation zone. The present invention is directed to an alkylation process having a feed fractionation zone, or butane splitter as it is commonly called, and a main fractionation zone following alkylation and separation of the hydrocarbon phase produced by the alkylation reaction.
Accordingly, an object of this invention is to provide an improved alkylation process.
Another object of this invention is to utilize the available heat in an alkylation plant and the process streams in a more efficient manner.
Another object of this invention is to recover isobutane which is normally lost with the normal butane vapor yielded from the main fractionator.
Another object of this invention is to provide a process of yielding a high purity normal paraffin stream.
It is another object of this invention to cut down on the energy cost of an alkylation process.
Other aspects, objects and the several advantages of the present invention will become apparent to those skilled in the art from a study of the disclosure, drawings, and the appended claims.